Biology subjects

Dahlin, K. J.- M.

Publications and source records attributed to Dahlin, K. J.- M..

3 recordsLinked to original sources

bioRxiv2025

Nonlinear effects of noise on outbreaks of mosquito-borne diseases

Mosquito-borne diseases are a significant and growing public health burden globally. Predictions about the future spread and impact of mosquito-borne disease outbreaks can help inform direct control and prevention measures. However, climate change is expected to increase weather variability, which may shape the future of mosquito-borne disease outbreaks globally. In this study, we sought to determine the effects of demographic and environmental noise (stochasticity) on the duration and size of outbreaks predicted by models of mosquito-borne disease. We developed a demographically and environmentally stochastic Ross-Macdonald model to assess how noise affects the probability of an outbreak, the peak number of cases, and the duration of outbreaks at increasing levels of the basic reproduction number (R0) and environmental noise strength. Increasing environmental noise lowers the risk of endemic disease from 100% down to almost 0%, but the largest outbreaks occur at intermediate environmental noise levels. In this case, if an outbreak dies out, it ends quickly. With noise present, R0 alone is insufficient to predict definitively whether an outbreak occurs. Surprisingly, our model suggests that increasing environmental noise may reduce the risk of endemic disease and epidemics due to more frequent extreme conditions dramatically affecting mosquito populations. Author SummaryClimate change is expected to cause drastic changes in the spread of mosquito-borne disease outbreaks, both in where they occur and in their size. A key aspect of climate change is an increase in the variability of weather factors, such as rainfall and temperature, factors that also play a crucial role in mosquito survival and reproduction. We created a mathematical model to help us understand how increases in variability might affect mosquito-borne disease outbreaks in the future. Results from our modeling suggest that, depending on current levels, future increases in environmental variability could either increase or decrease the size of future outbreaks. Our work highlights the need to better understand the connections between environmental changes and mosquito biology to inform efforts to forecast and suppress mosquito outbreaks.

ecology↗

bioRxiv2024

Fast-lived Vertebrate Hosts Exhibit Higher Potential for Mosquito-borne Parasite Transmission

The emergence of mosquito-borne zoonoses has continually increased over the past decade, posing a significant global public health challenge. Ecological theory can point to the characteristics of populations that make them more likely to form reservoirs of disease. The pace of life hypothesis posits that species with more rapid reproduction and shorter lifespans are more likely to be disease reservoirs than their slower-living cousins. Mathematical modeling suggests theoretical conditions under which this hypothesis is correct for directly- and environmentally-transmitted pathogens but its applicability to mosquito-borne disease systems has yet to be examined. We parameterized a mechanistic model with host trait data to investigate the link between the position of a species on the fast-slow life history continuum and the potential for it to spread mosquitoborne diseases. We evaluated the resulting relationships for four medically important mosquito species across their thermal niches and for four pathogens characterized by infection duration and the level of susceptibility of the focal host to infection. Finally, because the fast-slow life history continuum differs across taxonomic ranks, we considered the theory in the context of two orders of vertebrate hosts, Rodentia and Primates. After parameterizing our model, we found that, near universally across all the axes of variation considered, fast-lived hosts have higher transmission potential than slow-lived hosts. There was one exception: slower-lived hosts have higher transmission potential for parasites that cause long-enduring infections to which these hosts are highly susceptible. Generally, however, these connections hinge on the often unknown links between immunological traits, population density, and pace of life. Our analyses highlight immunological traits as a key knowledge gap with strong influence over the potential for transmission. Further investigation of the pace of life hypothesis will require a better understanding of how, for mosquito-borne parasitic infections, susceptibility and infection duration vary across the members of a taxonomic order.

ecology↗

bioRxiv2024

Coexistence of bacteria with a competition-colonization tradeoff on a dynamic coral host

Many macroscopic organisms enter into tightly linked symbiosis with microbial communities. Although experimental work has demonstrated the importance of these symbioses, a theoretical understanding of stable, multi-scale coexistence remains underdeveloped. Here, we explored how the competition-colonization tradeoff, a classic coexistence mechanism, operates when bacterial species compete for a dynamic biological host. Specifically, we introduce a model where corals are colonized by fast-growing mutualists and slow-growing pathogens. We found that the vital rates of the host coral influenced coexistence outcomes between bacterial types. Notably, pathogen-induced host death expanded the region of parameter space where coexistence was stable for all three species and mutualistic bacteria enabled coexistence in systems that would have otherwise collapsed. These findings provide new insights into the interplay between microbial interactions and macroscopic processes. Our work illustrates how host-microbe interactions can shape ecosystem stability, providing a theoretical framework applicable to a wide range of symbiotic systems.

ecology↗